General manager Ruben Amaro Jr. said today that lefthander J.A. Happ will remain in the Phillies rotation for the rest of the season, and raised the possibility of a six-man rotation that would utlilize both Pedro Martinez and Jamie Moyer as starters.

"Happ's not going out of anywhere," Amaro said, providing the first definitive answer about the young lefty's future after a week of speculation surrounding a possible return to the bullpen.

The Phillies general manager lauded Happ for maintaining his focus throughout a trying month that saw his name bandied about in trade rumors. For the previous week, the club had not ruled out sending Happ back to the bullpen in order to create a rotation spot for Martinez, who drew rave reviews in what was likely his last rehab outing Wednesday night. Martinez and Happ pitched on the same night, which would have made for a seamless transition. Plus, Happ started the season in the bullpen, while veteran Jamie Moyer is not suited for such a role.

But Amaro indicated that Happ is simply too valuable as a starter to consider moving him to the bullpen, especially after a complete game performance against the Rockies Wednesday night in which he allowed four hits and no runs and struck out a career-high 11.

Amaro called it "maybe one fo the best games we've pitched this year."

So where does that leave the decision-making process? Although Amaro said no decisions are final, Martinez is likely to join the Phillies' active roster sometime this weekend. The GM said that Martinez "threw very well" in striking out 11 in six innings at Double-A Reading.

"I think he can get major league hitters out with his stuff," Amaro said. "I know it was a minor league club, but when you have 11 strikeouts and no walks, that's good in Little League."

Amaro said that Martinez threw harder in his final inning than he did in his first. His fastball sat in the 86-to-90 range, topping out at 92.

But Martinez's induction into the rotation does not necessarily mean that Jamie Moyer is out of a job. Moyer will make his next start, Sunday, against the Marlins. At that point, Amaro said the Phillies could experiment with a six-man rotation, pitching certain guys on normal rest -- think Joe Blanton and Cliff Lee, and maybe Cole Hamels -- and others on five days. Happ has thrown 115 innings and his coming off a 127-pitch effort. The Phillies certainly could make an argument that he deserves another day off in addition to Monday's off day. That would open up a hole for Martinez to start on Tuesday in Chicago.

"We still haven't made a decision," Amaro said. "It's not out of the possibility to go with a six-man rotation."

In other news, Amaro said Chad Durbin pitched well in his rehab outing Wednesday night. The righthander will make another appearance Friday, then will return to Philadelphia. At that point, the team will decide whether he is ready to join the active roster, or if he needs another rehab start. Regardless, barring set-backs, he should be back with the club within the next week.